This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Last year we showed macaques intravenously infused with 2F5 were protected against vaginal SHIVBAL transmission in a dose-dependent manner. Animals intravenously infused with 25-50mg/kg 2F5 were completely protected against vaginal transmission (n=5), whereas 2/5 and 0/5 macaques were protected when infused with 5mg/kg, or placebo respectively. In the last year we have been performing PK and PD studies of vaginal secretion to determine the correlates of protection in vaginal surfaces needed for an antibody to prevent against vaginal transmission. To cross-validate functional mucosal antibody in vitro assays with protection against vaginal challenge, we have sent all vaginal fluids and plasma samples to Robin Shattock's lab for final data analysis and we expect to publish these studies this year.